The concept of using a patch port device for injecting and monitoring an electrical signal is well known. A patch port device is typically a passive symmetrical device, providing for an input port, an output port, a monitoring port, and an injection port. In the normal mode of operation, the patch port device simply allows for an input electrical signal to be passed through as an output electrical signal. However, there may occasionally be the need to inject another electrical signal as the output electrical signal or to monitor the input electrical signal. When an electrical cable is plugged into the monitoring port of the patch port device for monitoring the input electrical signal, the presence of the electrical cable at the monitoring port is physically detected so that the input electrical signal is no longer passed through as an output electrical signal. Instead, the input electrical signal is sent out to the electrical cable plugged in the monitoring port, controlled by a switch activated by the physical detection. Similarly, when an electrical cable is plugged into the injection port of the patch port device for injecting another electrical signal as the output electrical signal, the presence of the electrical cable at the injection port is physically detected so that the input electrical signal is no longer passed through as an output electrical signal. Instead, the injected signal coming from the electrical cable plugged in the injection port is sent out as the output electrical signal, controlled by a switch activated by the physical detection.
Prior networks relied on electrical lines to transmit information. However, fiber optic lines of newer systems are capable of much higher rates of transmission. As the use of optical networks becomes more prevalent, there is a need for an alternative to the patch port device described above that can provide for injection and monitoring of optical signals, as well as existing electrical signals, in addition to being able to provide for conversion between optical and electrical signals.